code: def add_model(self, model: GraphModelSpace):
      self.models.append(model)
      # Only optimize the root graph.
      self._merge_graph(model.root_graph)
  
imports: import copy
  from typing import Dict, Tuple, Any, Type, cast
  from nni.common.device import Device, CPUDevice
  from nni.mutable.utils import uid
  from nni.nas.space import Edge, Graph, GraphModelSpace, Node
  from nni.nas.space.graph_op import Cell, Operation, _IOPseudoOperation
label_desc: Use image node_id 2 for calling the LogicalPlan obj's underlying member method code with example usage: obj.add_model(model) without return types